21st Nov 2022 -

A quarter of all heat loss in a home occurs through the roof, making loft insulation a necessity for homeowners. There are a variety of ways to insulate a house, from installing insulation blankets between your loft joists, loose-fill insulation, fixing insulation boards to your roof, and blown-fibre insulation. Installing loft insulation materials can limit the heat escaping from your home, lowering your energy bills and saving you money. When looking for the best loft insulation products it is easy to feel out of your depth or confused. In this guide from Building Materials Nationwide, we’ll take you through an explanation of each of the main types of loft insulation, then compare them on two levels, their effectiveness and ease of use, and their costs to buy and install. 

Your Options in Loft Insulation Explained

There are four main types of loft insulation; Blanket insulation fitted between joists, loose-fill insulation, insulation boards attached to roof joists, and blown-fibre insulation. 

Blanket insulation comes in the form of rolls and slabs, made from mineral wools or sheep's wool. These will need to be cut to size and placed within the joists of your loft floor. The recommended level of insulation in a loft is 270mm, which may take it above the height of your joists, requiring the use of loft legs if you wish to install a solid floor above the insulation. This has long been the most popular method of loft insulation and is designed to last for decades.

Loose-fill insulation is made from a variety of lightweight materials like cork, mineral wool, or cellulose fibre. It consists of lightweight granules that are poured between joists for a loose fill, reaching a depth of about 270mm. It can be used as its own insulation, or used to top up existing insulation.

Loft Insulation boards are solid insulation boards, which can be fitted either over the joists of your roof or between them. To fit them between joists, you will need to leave space between the rafters and the insulation, to ensure the passage of air.

Blown-fibre insulation is a type of insulation that involves blowing mineral fibres around the joists of your loft, and certain types can also be blown into the roof joists. These fibres are bonded to stick together, offering a foam-like effect.

Looking For Quality Loft Insulation?

  1. Price from: £22.64 £27.17
  2. Call 01628 674910 To Discuss Availability

    • Applications floors, walls & roofs
    • Mineral Wool
    Price from: £43.40 £52.08

    • Various sizes available
    • Wall & Floor Insulation
    Price from: £54.01 £64.81

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What is the Best Loft Insulation Material?

A key benefit of blanket insulation is its straightforward installation process, with rolls or slabs cut to size and inserted within joists. When installed correctly, blanket loft insulation can offer a great level of thermal insulation. Key drawbacks include the bulky space requirements, an installation process that requires PPE to avoid skin irritation (if using mineral wool products), and the difficulties that can arise when fitting blanket insulation in small spaces or lofts with obstructions.

Loose-fill loft insulation materials are easy to install, as you can simply pour the granules between your loft joists, with no measuring or cutting required. It can be handy to use to top up gaps within the insulation or to insulate harder-to-reach spots that blanket insulation does not adequately cover. Loose-fill and blanket insulation make it more difficult to use your loft space, likely requiring the use of loft legs before you can lay solid flooring. If you are not laying a solid floor over it, a disadvantage of loose-fill loft insulation materials is that the granules can blow around, reducing the insulation in certain parts of your loft and requiring maintenance.

A construction worker wearing a plaid shirt and hat fitting sustainable Isover insulation within a loft area against a timber roof frame.

Insulation boards can offer a comfortable installation for a DIY enthusiast. They can be attached to the wooden joists of a slanted roof using a nail gun. Installing them between joists will be a more difficult process, as you need to leave a gap between the rafters and the insulation board. 

Compared to the flooring options, the insulation boards can be easily covered with plasterboard, while the floor joists can be easily boarded. If looking to convert your loft this method will also leave the loft area thoroughly insulated, allowing you to turn your loft into a warm living space. A disadvantage in smaller lofts can be the loss of roof space that comes with installing boards on the joists. To reach the recommended level of insulation, it may be more effective to use two insulation boards, one between the joists and one over them.

Blown-fibre loft insulation is great for reaching difficult areas, much like loose fill. There are risks that blown-fibre can reduce ventilation in your loft, risking humidity and dampness, which can damage roof timbers over time. A disadvantage of blown-fibre insulation is its messiness, which can make it difficult if you are looking to use your loft for storage or as a living space.

What Are the Best Loft Insulation Products for Price?

Blanket insulation is an affordable way to insulate your loft, particularly if you install it yourself. These products will provide a strong level of thermal insulation, and can be installed by you provided you fully cover your body. Loose-fill insulation is a more expensive option, particularly if you are using it to cover your entire loft floor. While it offers a slightly easier installation, products like Micafil are better used to top up insulation or fill difficult areas.

If you want to install Celotex General Application boards, they can be bought in 70mm or 200mm thicknesses. Boards are an expensive method, but a great choice if you are looking to make use of your loft space. While more difficult than blanket or loose-fill insulation, they can be installed yourself. Blown-fibre insulation requires specialist technology and experience, and can only be completed by a professional.

There are some factors that could increase costs, such as the presence of a water tank within your loft, or loose wires that might need to be moved. Below are some of the latest prices through our website for loft insulation.

  1. Price from: £37.99 £45.59
  2. Call 01628 674910 To Discuss Availability

    • Thermal Resistance: 0.034 W/mK
    • Application: Glass Mineral Wool
    Price from: £150.41 £180.49
  3. Price from: £90.73 £108.88

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What is the Best Loft Insulation for you?

In most cases, using traditional blanket insulation between the joists of your loft offers a great level of thermal insulation at a reasonable price. With protection and a little DIY experience, it can be fitted by you, and you can still use your loft for storage if you use loft legs to install a solid floor over it. 

Loose-fill insulation is great for topping up traditional insulation and filling difficult-to-reach holes, but is expensive to cover an entire loft, and can be difficult to keep in place in draughty lofts. If you are looking to use your insulated loft as a living space, then installing insulation boards under your pitched roof is a great choice to avoid a cold loft, albeit an expensive one. Blown-fibre insulation can cover difficult-to-reach areas, but is costly and can’t be installed by you. It can also cause issues with dampness in some lofts.

Our Comprehensive Range of Loft Insulation Materials

At Building Materials Nationwide we stock a wide variety of high-quality branded loft insulation products. We offer a range of blanket insulation for sale, including slabs and loft insulation rolls made from mineral fibre or sheep’s wool, many with fire-resistant features. 

We also have a range of insulation boards that can be installed underneath a pitched roof. We offer delivery across the UK on our range of products. Energy-saving loft insulation can help reduce your carbon footprint whilst saving you money.

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